Ab Initio Study on Mixed Inorganic/Organic Ligand Sandwich Clusters: BzTMC60, TM = Sc−Co

Abstract

We have systematically investigated mixed inorganic/organic ligand sandwich clusters comprised of 3d transition metal (TM) atoms with C(60) and benzene (Bz) molecules, BzTMC(60), by using all electron density functional theory. We found the bonding type between TM and C(60) in the ground state evolves from eta(6) (TM = Sc-Cr) to eta(5) (TM = Mn) and then to eta(2) (TM = Fe, Co) with increasing number of d electrons of TM. The BzTMC(60) clusters (TM = Sc-Co) are of high stability through ionic-covalent interactions. The BzCrC(60) cluster has the lowest binding energy due to its largest spin-flip energy and the weakest ionic bonding interaction between the CrBz unit and C(60). With the exception of BzTiC(60) being triplet, all the BzTMC(60) clusters energetically prefer the lowest available spin states, e.g., the ground spin state is either a singlet (with an even number of electrons) or a doublet (with an odd number of electrons). Moreover, the magnetic properties of BzTMC(60) show clear dependence to the bond type between TM and C(60), and the eta(5)-ligand configurations tend to be in high spin states.